This invention relates to recoil compensators attached to or integral with the muzzle of the barrel of firearms. More particularly, the present invention relates to handguns, rifles or automatic shoulder fired weapons where there is a need to reduce the recoil effect of firing such weapons, specifically the upward jump or climb of the muzzle of the barrel. This device uses a series of Laval nozzles to match the expansion of propellant gasses from the barrel to the atmosphere to achieve the maximum potential reactive thrust possible to counteract these recoil forces. A second important feature of the design is that the mass flow through the nozzle array be matched to the available propellant gas reservoir in the barrel. In a very rough way, this condition is met if the total throat area of the nozzle array does not exceed the barrel cross-sectional area.
Numerous muzzle attachment devices have been developed in the past to reduce the recoil effects of manual and automatic fire weapons; however, these devices have been found to be only marginally effective in reducing recoil. Many of these devices consist of straight holes or slots cut into the muzzle of the rifle or machine gun in an attempt to use the reactive force of the propellant gasses escaping upward to compensate for recoil forces causing muzzle climb (the most serious cause of loss of aiming accuracy or slowing the return to target for subsequent shots). Other types of recoil reduction devices use either the propellant gasses or mechanical linkage with the barrel and breech mechanism, or both, to provide for a slower absorption of the recoil forces by the shooter. These techniques, often realized in the basic design of the automatic loading mechanism of the firearm (as the M-1 Garand, for example), are effective in improving recoil control but do not reduce the total momentum imparted by the recoil forces. Instead, the recoil acceleration forces are reduced and prolonged (the integral remaining constant). Interest in recoil reduction, particularly in controlling muzzle climb during full automatic firing of military automatic rifles such as the M-16, has increased with the desire to obtain more effective direction of automatic small arms fire. In most lightweight M-14, AR-15, and M-16 tests only the first shot of the automatic burst provided a target hit in the tests quoted, whereas the M1918A2 [BAR] produced 80 percent hits in full automatic fire. The BAR is, of course, a heavy machine rifle whose mechanism and overall weight tends to compensate for recoil and muzzle climb forces. In Cutts U.S. Pat. Nos. 1,605,393 and 1,636,357, Ruth U.S. Pat. No. 3,155,003, and Hughes U.S. Pat. No. 2,212,685, the anticlimb devices have a central bore larger than the bore of the gun barrel and a series of straight, angular or flared ports extending inside the cylinder.
All of the above-cited devices attempt to use the reactive forces of the propellant gases escaping upward to compensate for the rearward and upward recoil forces. However, all of the prior art devices fail to match the area of the through narrows of the port means to the cross-sectional area of the bore and all of the prior art devices fail to provide a matched or optimum expansion of the propellant gases from the through bore to the atmosphere to provide maximum potential reactive thrust.